Optical imaging lens

ABSTRACT

An optical imaging lens includes a first lens element to an eighth lens element, and each lens element has an object-side surface and an image-side surface. The first lens element has positive refracting power, an optical axis region of the image-side surface of the first lens element is concave, the second lens element has negative refracting power, a periphery region of the object-side surface of the second lens element is concave, and an optical axis region of the object-side surface of the eighth lens element is convex. The lens elements having refracting power included by the optical imaging lens are only the eight lens elements described above. The optical imaging lens satisfies the following conditions: D61t82/D21t42≥1.750.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to an optical imaging lens.Specifically speaking, the present invention is directed to an opticalimaging lens for use in a portable electronic device such as a mobilephone, a camera, a tablet personal computer, or a personal digitalassistant (PDA) for taking pictures or for recording videos.

2. Description of the Prior Art

The specifications of portable electronic devices are changing with eachpassing day, and the optical imaging lenses in its key components arealso developing more diversified. For the main lens of portableelectronic devices, it not only requires a larger aperture and maintainsa shorter system length, but also pursues higher pixels and higherresolution. However, the optical imaging lens with high pixels needs toincrease the image height of the lens, and larger image sensors are usedto receive imaging ray to improve pixel requirements. However, thedesign of large aperture allows the lens to receive more imaging ray,but at the same time, it makes the design more difficult, while the highpixel increases the resolution of the lens, which also increases thedesign difficulty in combination with the large aperture design.

Therefore, how to add multiple lens elements in a length-limited systemto increase the resolution and simultaneously increase the aperture andthe image height is a problem that needs to be challenged and solved.

SUMMARY OF THE INVENTION

In light of the above, the present invention proposes an optical imaginglens of eight lens elements which is shorter in system length, hasensured imaging quality, and has smaller f-number, larger image heightand technically possible. The optical imaging lens of eight lenselements of the present invention from an object side to an image sidein order along an optical axis has a first lens element, a second lenselement, a third lens element, a fourth lens element, a fifth lenselement, a sixth lens element, a seventh lens element and an eighth lenselement. Each first lens element, second lens element, third lenselement, fourth lens element, fifth lens element, sixth lens element,seventh lens element and eighth lens element respectively has anobject-side surface which faces toward the object side to allow imagingrays to pass through as well as an image-side surface which faces towardthe image side to allow the imaging rays to pass through.

In one embodiment of the present invention, the first lens element haspositive refracting power, and an optical axis region of the image-sidesurface of the first lens element is concave, the second lens hasnegative refracting power, a periphery region of the object-side surfaceof the second lens element is concave, and an optical axis region of theobject-side surface of the eighth lens element is convex. The lenselements having refracting power included by the optical imaging lensare only the eight lens elements described above, wherein the opticalimaging lens satisfies the relationships: D61t82/D21t42≥1.750 whereinD61t82 is a distance from the object-side surface of the sixth lenselement to the image-side surface of the eighth lens element along theoptical axis, D21t42 is a distance from the object-side surface of thesecond lens element to the image-side surface of the fourth lens elementalong the optical axis.

In another embodiment of the present invention, the first lens elementhas positive refracting power, and a periphery region of the image-sidesurface of the first lens element is concave, a periphery region of theimage-side surface of the fourth lens element is convex, a peripheryregion of the object-side surface of the sixth lens element is concave,the seventh lens element has positive refracting power, an optical axisregion of the object-side surface of the eighth lens element is convex.The lens elements having refracting power included by the opticalimaging lens are only the eight lens elements described above, whereinthe optical imaging lens satisfies the relationships:D61t82/D21t42≥2.000, wherein D61t82 is a distance from the object-sidesurface of the sixth lens element to the image-side surface of theeighth lens element along the optical axis, D21t42 is a distance fromthe object-side surface of the second lens element to the image-sidesurface of the fourth lens element along the optical axis.

In another embodiment of the present invention, the first lens elementhas positive refracting power, and an optical axis region of theimage-side surface of the first lens element is concave, a peripheryregion of the object-side surface of the second lens element is concave,a periphery region of the image-side surface of the third lens elementis convex, and an optical axis region of the object-side surface of theeighth lens element is convex. The lens elements having refracting powerincluded by the optical imaging lens are only the eight lens elementsdescribed above, wherein the optical imaging lens satisfies therelationships: ν1+ν2+ν3+ν4+ν5≤205.000, where ν1 is an Abbe number of thefirst lens element, ν2 is an Abbe number of the second lens element, ν3is an Abbe number of the third lens element, ν4 is an Abbe number of thefourth lens element; ν5 is an Abbe number of the fifth lens element.

In the optical imaging lens of the present invention, the embodimentsmay also selectively satisfy the following optical conditions:

1. ν4+ν5≤70.100;

2. ν4≤35.000;

3. EFL*Fno/ImgH≤1.800;

4. ALT/AAG≤2.000;

5. (T1+T2+T5+G23)/(T3+G45)≤1.900;

6. (T7+T8+G23)/(T4+G12+G45)≤3.200;

7. D42t71/(T3+G12)≤2.700;

8. TTL/ImgH≤1.300;

9. (ALT+BFL)/AAG48≤4.150;

10. (T1+T2+T5+G34)/(T3+G56)≤2.000;

11. (T7+T8+G34)/(T4+G12+G56)≤2.200;

12. D42t71/(T3+G78)≤2.200;

13. 49.000≤ν7≤60.000;

14. TL*Fno/ImgH≤2.000;

15. ALT/(T3+T6+G12)≤3.100;

16. (T1+T2+T5+G67)/(T3+G78)≤2.000; and

17. (T7+T8+G67)/(T4+G12+G78)≤2.400.

In the present invention, T1 is a thickness of the first lens elementalong the optical axis, T2 is a thickness of the second lens elementalong the optical axis, T3 is a thickness of the third lens elementalong the optical axis, T4 is a thickness of the fourth lens elementalong the optical axis, T5 is a thickness of the fifth lens elementalong the optical axis, T6 is a thickness of the sixth lens elementalong the optical axis, T7 is a thickness of the seventh lens elementalong the optical axis, T8 is a thickness of the eighth lens elementalong the optical axis, G12 is an air gap between the first lens elementand the second lens element along the optical axis, G23 is an air gapbetween the second lens element and the third lens element along theoptical axis, G34 is an air gap between the third lens element and thefourth lens element along the optical axis, G45 is an air gap betweenthe fourth lens element and the fifth lens element along the opticalaxis, G56 is an air gap between the fifth lens element and the sixthlens element along the optical axis, G67 is an air gap between the sixthlens element and the seventh lens element along the optical axis, G78 isan air gap between the seventh lens element and the eighth lens elementalong the optical axis, ALT is a sum of the thicknesses of eight lenselements from the first lens element to the eighth lens element alongthe optical axis, TL is a distance from the object-side surface of thefirst lens element to the image-side surface of the eighth lens elementalong the optical axis, TTL is the distance from the object-side surfaceof the first lens element to an imaging plane along the optical axis,BFL is a distance from the image-side surface of the eighth lens elementto an image plane along the optical axis, AAG is a sum of seven air gapsfrom the first lens element to the eighth lens element along the opticalaxis, EFL is an effective focal length of the optical imaging lens; ImgHis an image height of the optical imaging lens, and Fno is a f-number ofthe optical imaging lens.

Besides, the Abbe number of the first lens element is ν1; the Abbenumber of the second lens element is ν2; the Abbe number of the thirdlens element is ν3; the Abbe number of the fourth lens element is ν4;the Abbe number of the fifth lens element is ν5; an Abbe number of thesixth lens element is ν6; an Abbe number of the seventh lens element isν7, an Abbe number of the eighth lens element is ν8.

In the present invention, further defining: D21t42 is the distance fromthe object-side surface of the second lens element to the image-sidesurface of the fourth lens element along the optical axis; D42t71 is adistance from the image-side surface of the fourth lens element to theobject-side surface of the seventh lens element along the optical axis;D61t82 is the distance from the object-side surface of the sixth lenselement to the image-side surface of the eighth lens element along theoptical axis; AAG48 is a sum of four air gaps from the fourth lenselement to the eighth lens element along the optical axis, that is, thesum of G45, G56, G67 and G78.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrates the methods for determining the surface shapes andfor determining optical region or periphery region of one lens element.

FIG. 6 illustrates a first example of the optical imaging lens of thepresent invention.

FIG. 7A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 7B illustrates the field curvature aberration on the sagittaldirection of the first example.

FIG. 7C illustrates the field curvature aberration on the tangentialdirection of the first example.

FIG. 7D illustrates the distortion of the first example.

FIG. 8 illustrates a second example of the optical imaging lens of thepresent invention.

FIG. 9A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 9B illustrates the field curvature aberration on the sagittaldirection of the second example.

FIG. 9C illustrates the field curvature aberration on the tangentialdirection of the second example.

FIG. 9D illustrates the distortion of the second example.

FIG. 10 illustrates a third example of the optical imaging lens of thepresent invention.

FIG. 11A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 11B illustrates the field curvature aberration on the sagittaldirection of the third example.

FIG. 11C illustrates the field curvature aberration on the tangentialdirection of the third example.

FIG. 11D illustrates the distortion of the third example.

FIG. 12 illustrates a fourth example of the optical imaging lens of thepresent invention.

FIG. 13A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 13B illustrates the field curvature aberration on the sagittaldirection of the fourth example.

FIG. 13C illustrates the field curvature aberration on the tangentialdirection of the fourth example.

FIG. 13D illustrates the distortion of the fourth example.

FIG. 14 illustrates a fifth example of the optical imaging lens of thepresent invention.

FIG. 15A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 15B illustrates the field curvature aberration on the sagittaldirection of the fifth example.

FIG. 15C illustrates the field curvature aberration on the tangentialdirection of the fifth example.

FIG. 15D illustrates the distortion of the fifth example.

FIG. 16 illustrates a sixth example of the optical imaging lens of thepresent invention.

FIG. 17A illustrates the longitudinal spherical aberration on the imageplane of the sixth example.

FIG. 17B illustrates the field curvature aberration on the sagittaldirection of the sixth example.

FIG. 17C illustrates the field curvature aberration on the tangentialdirection of the sixth example.

FIG. 17D illustrates the distortion of the sixth example.

FIG. 18 illustrates a seventh example of the optical imaging lens of thepresent invention.

FIG. 19A illustrates the longitudinal spherical aberration on the imageplane of the seventh example.

FIG. 19B illustrates the field curvature aberration on the sagittaldirection of the seventh example.

FIG. 19C illustrates the field curvature aberration on the tangentialdirection of the seventh example.

FIG. 19D illustrates the distortion of the seventh example.

FIG. 20 illustrates an eighth example of the optical imaging lens of thepresent invention.

FIG. 21A illustrates the longitudinal spherical aberration on the imageplane of the eighth example.

FIG. 21B illustrates the field curvature aberration on the sagittaldirection of the eighth example.

FIG. 21C illustrates the field curvature aberration on the tangentialdirection of the eighth example.

FIG. 21D illustrates the distortion of the eighth example.

FIG. 22 illustrates a ninth example of the optical imaging lens of thepresent invention.

FIG. 23A illustrates the longitudinal spherical aberration on the imageplane of the ninth example.

FIG. 23B illustrates the field curvature aberration on the sagittaldirection of the ninth example.

FIG. 23C illustrates the field curvature aberration on the tangentialdirection of the ninth example.

FIG. 23D illustrates the distortion of the ninth example.

FIG. 24 shows the optical data of the first example of the opticalimaging lens.

FIG. 25 shows the aspheric surface data of the first example.

FIG. 26 shows the optical data of the second example of the opticalimaging lens.

FIG. 27 shows the aspheric surface data of the second example.

FIG. 28 shows the optical data of the third example of the opticalimaging lens.

FIG. 29 shows the aspheric surface data of the third example.

FIG. 30 shows the optical data of the fourth example of the opticalimaging lens.

FIG. 31 shows the aspheric surface data of the fourth example.

FIG. 32 shows the optical data of the fifth example of the opticalimaging lens.

FIG. 33 shows the aspheric surface data of the fifth example.

FIG. 34 shows the optical data of the sixth example of the opticalimaging lens.

FIG. 35 shows the aspheric surface data of the sixth example.

FIG. 36 shows the optical data of the seventh example of the opticalimaging lens.

FIG. 37 shows the aspheric surface data of the seventh example.

FIG. 38 shows the optical data of the eighth example of the opticalimaging lens.

FIG. 39 shows the aspheric surface data of the eighth example.

FIG. 40 shows the optical data of the ninth example of the opticalimaging lens.

FIG. 41 shows the aspheric surface data of the ninth example.

FIG. 42 shows some important ratios in the examples.

DETAILED DESCRIPTION

The terms “optical axis region”, “periphery region”, “concave”, and“convex” used in this specification and claims should be interpretedbased on the definition listed in the specification by the principle oflexicographer.

In the present disclosure, the optical system may comprise at least onelens element to receive imaging rays that are incident on the opticalsystem over a set of angles ranging from parallel to an optical axis toa half field of view (HFOV) angle with respect to the optical axis. Theimaging rays pass through the optical system to produce an image on animage plane. The term “a lens element having positive refracting power(or negative refracting power)” means that the paraxial refracting powerof the lens element in Gaussian optics is positive (or negative). Theterm “an object-side (or image-side) surface of a lens element” refersto a specific region of that surface of the lens element at whichimaging rays can pass through that specific region. Imaging rays includeat least two types of rays: a chief ray Lc and a marginal ray Lm (asshown in FIG. 1). An object-side (or image-side) surface of a lenselement can be characterized as having several regions, including anoptical axis region, a periphery region, and, in some cases, one or moreintermediate regions, as discussed more fully below.

FIG. 1 is a radial cross-sectional view of a lens element 100. Tworeferential points for the surfaces of the lens element 100 can bedefined: a central point, and a transition point. The central point of asurface of a lens element is a point of intersection of that surface andthe optical axis I. As illustrated in FIG. 1, a first central point CP1may be present on the object-side surface 110 of lens element 100 and asecond central point CP2 may be present on the image-side surface 120 ofthe lens element 100. The transition point is a point on a surface of alens element, at which the line tangent to that point is perpendicularto the optical axis I. The optical boundary OB of a surface of the lenselement is defined as a point at which the radially outermost marginalray Lm passing through the surface of the lens element intersects thesurface of the lens element. All transition points lie between theoptical axis I and the optical boundary OB of the surface of the lenselement. If multiple transition points are present on a single surface,then these transition points are sequentially named along the radialdirection of the surface with reference numerals starting from the firsttransition point. For example, the first transition point, e.g., TP1,(closest to the optical axis I), the second transition point, e.g., TP2,(as shown in FIG. 4), and the Nth transition point (farthest from theoptical axis I).

The region of a surface of the lens element from the central point tothe first transition point TP1 is defined as the optical axis region,which includes the central point. The region located radially outside ofthe farthest Nth transition point from the optical axis I to the opticalboundary OB of the surface of the lens element is defined as theperiphery region. In some embodiments, there may be intermediate regionspresent between the optical axis region and the periphery region, withthe number of intermediate regions depending on the number of thetransition points.

The shape of a region is convex if a collimated ray being parallel tothe optical axis I and passing through the region is bent toward theoptical axis I such that the ray intersects the optical axis I on theimage side A2 of the lens element. The shape of a region is concave ifthe extension line of a collimated ray being parallel to the opticalaxis I and passing through the region intersects the optical axis I onthe object side A1 of the lens element.

Additionally, referring to FIG. 1, the lens element 100 may also have amounting portion 130 extending radially outward from the opticalboundary OB. The mounting portion 130 is typically used to physicallysecure the lens element to a corresponding element of the optical system(not shown). Imaging rays do not reach the mounting portion 130. Thestructure and shape of the mounting portion 130 are only examples toexplain the technologies, and should not be taken as limiting the scopeof the present disclosure. The mounting portion 130 of the lens elementsdiscussed below may be partially or completely omitted in the followingdrawings.

Referring to FIG. 2, optical axis region Z1 is defined between centralpoint CP and first transition point TP1. Periphery region Z2 is definedbetween TP1 and the optical boundary OB of the surface of the lenselement. Collimated ray 211 intersects the optical axis I on the imageside A2 of lens element 200 after passing through optical axis regionZ1, i.e., the focal point of collimated ray 211 after passing throughoptical axis region Z1 is on the image side A2 of the lens element 200at point R in FIG. 2. Accordingly, since the ray itself intersects theoptical axis I on the image side A2 of the lens element 200, opticalaxis region Z1 is convex. On the contrary, collimated ray 212 divergesafter passing through periphery region Z2. The extension line EL ofcollimated ray 212 after passing through periphery region Z2 intersectsthe optical axis I on the object side A1 of lens element 200, i.e., thefocal point of collimated ray 212 after passing through periphery regionZ2 is on the object side A1 at point M in FIG. 2. Accordingly, since theextension line EL of the ray intersects the optical axis I on the objectside A1 of the lens element 200, periphery region Z2 is concave. In thelens element 200 illustrated in FIG. 2, the first transition point TP1is the border of the optical axis region and the periphery region, i.e.,TP1 is the point at which the shape changes from convex to concave.

Alternatively, there is another way for a person having ordinary skillin the art to determine whether an optical axis region is convex orconcave by referring to the sign of “Radius” (the “R” value), which isthe paraxial radius of shape of a lens surface in the optical axisregion. The R value is commonly used in conventional optical designsoftware such as Zemax and CodeV. The R value usually appears in thelens data sheet in the software. For an object-side surface, a positiveR value defines that the optical axis region of the object-side surfaceis convex, and a negative R value defines that the optical axis regionof the object-side surface is concave. Conversely, for an image-sidesurface, a positive R value defines that the optical axis region of theimage-side surface is concave, and a negative R value defines that theoptical axis region of the image-side surface is convex. The resultfound by using this method should be consistent with the methodutilizing intersection of the optical axis by rays/extension linesmentioned above, which determines surface shape by referring to whetherthe focal point of a collimated ray being parallel to the optical axis Iis on the object-side or the image-side of a lens element. As usedherein, the terms “a shape of a region is convex (concave),” “a regionis convex (concave),” and “a convex- (concave-) region,” can be usedalternatively.

FIG. 3, FIG. 4 and FIG. 5 illustrate examples of determining the shapeof lens element regions and the boundaries of regions under variouscircumstances, including the optical axis region, the periphery region,and intermediate regions as set forth in the present specification.

FIG. 3 is a radial cross-sectional view of a lens element 300. Asillustrated in FIG. 3, only one transition point TP1 appears within theoptical boundary OB of the image-side surface 320 of the lens element300. Optical axis region Z1 and periphery region Z2 of the image-sidesurface 320 of lens element 300 are illustrated. The R value of theimage-side surface 320 is positive (i.e., R>0). Accordingly, the opticalaxis region Z1 is concave.

In general, the shape of each region demarcated by the transition pointwill have an opposite shape to the shape of the adjacent region(s).Accordingly, the transition point will define a transition in shape,changing from concave to convex at the transition point or changing fromconvex to concave. In FIG. 3, since the shape of the optical axis regionZ1 is concave, the shape of the periphery region Z2 will be convex asthe shape changes at the transition point TP1.

FIG. 4 is a radial cross-sectional view of a lens element 400. Referringto FIG. 4, a first transition point TP1 and a second transition pointTP2 are present on the object-side surface 410 of lens element 400. Theoptical axis region Z1 of the object-side surface 410 is defined betweenthe optical axis I and the first transition point TP1. The R value ofthe object-side surface 410 is positive (i.e., R>0). Accordingly, theoptical axis region Z1 is convex.

The periphery region Z2 of the object-side surface 410, which is alsoconvex, is defined between the second transition point TP2 and theoptical boundary OB of the object-side surface 410 of the lens element400. Further, intermediate region Z3 of the object-side surface 410,which is concave, is defined between the first transition point TP1 andthe second transition point TP2. Referring once again to FIG. 4, theobject-side surface 410 includes an optical axis region Z1 locatedbetween the optical axis I and the first transition point TP1, anintermediate region Z3 located between the first transition point TP1and the second transition point TP2, and a periphery region Z2 locatedbetween the second transition point TP2 and the optical boundary OB ofthe object-side surface 410. Since the shape of the optical axis regionZ1 is designed to be convex, the shape of the intermediate region Z3 isconcave as the shape of the intermediate region Z3 changes at the firsttransition point TP1, and the shape of the periphery region Z2 is convexas the shape of the periphery region Z2 changes at the second transitionpoint TP2.

FIG. 5 is a radial cross-sectional view of a lens element 500. Lenselement 500 has no transition point on the object-side surface 510 ofthe lens element 500. For a surface of a lens element with no transitionpoint, for example, the object-side surface 510 the lens element 500,the optical axis region Z1 is defined as the region between 0-50% of thedistance between the optical axis I and the optical boundary OB of thesurface of the lens element and the periphery region is defined as theregion between 50%-100% of the distance between the optical axis I andthe optical boundary OB of the surface of the lens element. Referring tolens element 500 illustrated in FIG. 5, the optical axis region Z1 ofthe object-side surface 510 is defined between the optical axis I and50% of the distance between the optical axis I and the optical boundaryOB. The R value of the object-side surface 510 is positive (i.e., R>0).Accordingly, the optical axis region Z1 is convex. For the object-sidesurface 510 of the lens element 500, because there is no transitionpoint, the periphery region Z2 of the object-side surface 510 is alsoconvex. It should be noted that lens element 500 may have a mountingportion (not shown) extending radially outward from the periphery regionZ2.

As shown in FIG. 6, the optical imaging lens 1 of eight lens elements ofthe present invention, sequentially located from an object side A1(where an object is located) to an image side A2 along an optical axisI, has an aperture stop (ape. stop) 99, a first lens element 10, asecond lens element 20, a third lens element 30, a fourth lens element40, a fifth lens element 50, a sixth lens element 60, a seventh lenselement 70, an eighth lens element 80, a filter 90 and an image plane91. Generally speaking, the first lens element 10, the second lenselement 20, the third lens element 30, the fourth lens element 40, thefifth lens element 50, the sixth lens element 60, the seventh lenselement 70 and the eighth lens element 80 may be made of a transparentplastic material but the present invention is not limited to this, andeach has an appropriate refracting power. In the present invention, lenselements having refracting power included by the optical imaging lens 1are only the eight lens elements described above. The optical axis I isthe optical axis of the entire optical imaging lens 1, and the opticalaxis of each of the lens elements coincides with the optical axis of theoptical imaging lens 1.

Furthermore, the optical imaging lens 1 includes an aperture stop (ape.stop) 99 disposed in an appropriate position. In FIG. 6, the aperturestop 99 is disposed between the first lens element 10 and object sideA1. When light emitted or reflected by an object (not shown) which islocated at the object side A1 enters the optical imaging lens 1 of thepresent invention, it forms a clear and sharp image on the image plane91 at the image side A2 after passing through the aperture stop 80, thefirst lens element 10, the second lens element 20, the third lenselement 30, the fourth lens element 40, the fifth lens element 50, thesixth lens element 60, the seventh lens element 70, the eighth lenselement 80 and the filter 90. In one embodiment of the presentinvention, the optional filter 90 may be a filter of various suitablefunctions, for example, the filter 90 may be an infrared cut filter (IRcut filter), placed between the eighth lens element 80 and the imageplane 91.

Each lens element in the optical imaging lens 1 of the present inventionhas an object-side surface facing toward the object side A1 as well asan image-side surface facing toward the image side A2. For example, thefirst lens element 10 has an object-side surface 11 and an image-sidesurface 12; the second lens element 20 has an object-side surface 21 andan image-side surface 22; the third lens element 30 has an object-sidesurface 31 and an image-side surface 32; the fourth lens element 40 hasan object-side surface 41 and an image-side surface 42; the fifth lenselement 50 has an object-side surface 51 and an image-side surface 52;the sixth lens element 60 has an object-side surface 61 and animage-side surface 62; the seventh lens element 70 has an object-sidesurface 71 and an image-side surface 72; and the eighth lens element 80has an object-side surface 81 and an image-side surface 82. In addition,each object-side surface and image-side surface in the optical imaginglens 1 of the present invention has an optical axis region and aperiphery region.

Each lens element in the optical imaging lens 1 of the present inventionfurther has a thickness T along the optical axis I. For example, thefirst lens element 10 has a first lens element thickness T1, the secondlens element 20 has a second lens element thickness T2, the third lenselement 30 has a third lens element thickness T3, the fourth lenselement 40 has a fourth lens element thickness T4, the fifth lenselement 50 has a fifth lens element thickness T5, the sixth lens element60 has a sixth lens element thickness T6, the seventh lens element 70has a seventh lens element thickness T7, the eighth lens element 80 hasan eighth lens element thickness T8. Therefore, the sum of thethicknesses of eight lens elements from the first lens element 10 to theeighth lens element 80 in the optical imaging lens 1 along the opticalaxis I is ALT=T1+T2+T3+T4+T5+T6+T7+T8.

In addition, between two adjacent lens elements in the optical imaginglens 1 of the present invention there may be an air gap along theoptical axis I. For example, there is an air gap G12 disposed betweenthe first lens element 10 and the second lens element 20, an air gap G23disposed between the second lens element 20 and the third lens element30, an air gap G34 disposed between the third lens element 30 and thefourth lens element 40, an air gap G45 disposed between the fourth lenselement 40 and the fifth lens element 50, an air gap G56 disposedbetween the fifth lens element 50 and the sixth lens element 60, an airgap G67 disposed between the sixth lens element 60 and the seventh lenselement 70 as well as an air gap G78 disposed between the seventh lenselement 70 and the eighth lens element 80. Therefore, the sum of sevenair gaps from the first lens element 10 to the eighth lens element 80along the optical axis I is AAG=G12+G23+G34+G45+G56+G67+G78.

In addition, a distance from the object-side surface 11 of the firstlens element 10 to the image plane 91 along the optical axis I is TTL,namely a system length of the optical imaging lens 1; an effective focallength of the optical imaging lens element is EFL; a distance from theobject-side surface 11 of the first lens element 10 to the image-sidesurface 82 of the eighth lens element 80 along the optical axis I is TL;HFOV stands for the half field of view which is half of the field ofview of the entire optical imaging lens element system; ImgH is an imageheight of the optical imaging lens 1, and Fno is a f-number of theoptical imaging lens 1.

When the filter 90 is placed between the eighth lens element 80 and theimage plane 91, the air gap between the eighth lens element 80 and thefilter 90 along the optical axis I is G8F; the thickness of the filter90 along the optical axis I is TF; the air gap between the filter 90 andthe image plane 91 along the optical axis I is GFP; and the distancefrom the image-side surface 82 of the eighth lens element 80 to theimage plane 91 along the optical axis I is BFL. Therefore,BFL=G8F+TF+GFP.

Furthermore, a focal length of the first lens element 10 is f1; a focallength of the second lens element 20 is f2; a focal length of the thirdlens element 30 is f3; a focal length of the fourth lens element 40 isf4; a focal length of the fifth lens element 50 is f5; a focal length ofthe sixth lens element 60 is f6; a focal length of the seventh lenselement 70 is f7; a focal length of the eighth lens element 80 is f8; arefractive index of the first lens element 10 is n1; a refractive indexof the second lens element 20 is n2; a refractive index of the thirdlens element 30 is n3; a refractive index of the fourth lens element 40is n4; a refractive index of the fifth lens element 50 is n5; arefractive index of the sixth lens element 60 is n6; a refractive indexof the seventh lens element 70 is n7; a refractive index of the eighthlens element 80 is n8; an Abbe number of the first lens element 10 isν1; an Abbe number of the second lens element 20 is ν2; an Abbe numberof the third lens element 30 is ν3; and an Abbe number of the fourthlens element 40 is ν4; an Abbe number of the fifth lens element 50 isν5; an Abbe number of the sixth lens element 60 is ν6; an Abbe number ofthe seventh lens element 70 is ν7; and an Abbe number of the eighth lenselement 80 is ν8.

In the present invention, further defining: D21t42 is a distance fromthe object-side surface 21 of the second lens element 20 to theimage-side surface of 42 the fourth lens element 40 along the opticalaxis I; D42t71 is a distance from the image-side surface 42 of thefourth lens element 40 to the object-side surface 71 of the seventh lenselement 70 along the optical axis I; D61t82 is a distance from theobject-side surface 61 of the sixth lens element 60 to the image-sidesurface 82 of the eighth lens element 80 along the optical axis I; AAG48is a sum of four air gaps from the fourth lens element 40 to the eighthlens element 80 along the optical axis I, that is, the sum of G45, G56,G67 and G78.

First Example

Please refer to FIG. 6 which illustrates the first example of theoptical imaging lens 1 of the present invention. Please refer to FIG. 7Afor the longitudinal spherical aberration on the image plane 91 of thefirst example; please refer to FIG. 7B for the field curvatureaberration on the sagittal direction; please refer to FIG. 7C for thefield curvature aberration on the tangential direction; and please referto FIG. 7D for the distortion aberration. The Y axis of the sphericalaberration in each example is “field of view” for 1.0. The Y axis of theastigmatic field and the distortion in each example stands for “imageheight” (ImgH), which is 4.500 mm.

The optical imaging lens 1 of the first example exclusively has eightlens elements 10, 20, 30, 40, 50, 60, 70 and 80 with refracting power.The optical imaging lens 1 also has an aperture stop 99. The aperturestop 99 is provided between the first lens element 10 and the objectside A1.

The first lens element 10 has positive refracting power. An optical axisregion 13 of the object-side surface 11 of the first lens element 10 isconvex, and a periphery region 14 of the object-side surface 11 of thefirst lens element 10 is convex. An optical axis region 16 of theimage-side surface 12 of the first lens element 10 is concave, and aperiphery region 17 of the image-side surface 12 of the first lenselement 10 is concave. Besides, both the object-side surface 11 and theimage-side surface 12 of the first lens element 10 are asphericalsurfaces, but it is not limited thereto.

The second lens element 20 has negative refracting power. An opticalaxis region 23 of the object-side surface 21 of the second lens element20 is concave, and a periphery region 24 of the object-side surface 21of the second lens element 20 is concave. An optical axis region 26 ofthe image-side surface 22 of the second lens element 20 is convex, and aperiphery region 27 of the image-side surface 22 of the second lenselement 20 is concave. Besides, both the object-side surface 21 and theimage-side surface 22 of the second lens element 20 are asphericalsurfaces, but it is not limited thereto.

The third lens element 30 has positive refracting power. An optical axisregion 33 of the object-side surface 31 of the third lens element 30 isconvex, and a periphery region 34 of the object-side surface 31 of thethird lens element 30 is convex. An optical axis region 36 of theimage-side surface 32 of the third lens element 30 is convex, and aperiphery region 37 of the image-side surface 32 of the third lenselement 30 is convex. Besides, both the object-side surface 31 and theimage-side surface 32 of the third lens element 30 are asphericalsurfaces, but it is not limited thereto.

The fourth lens element 40 has negative refracting power. An opticalaxis region 43 of the object-side surface 41 of the fourth lens element40 is concave, and a periphery region 44 of the object-side surface 41of the fourth lens element 40 is concave. An optical axis region 46 ofthe image-side surface 42 of the fourth lens element 40 is convex, and aperiphery region 47 of the image-side surface 42 of the fourth lenselement 40 is convex. Besides, both the object-side surface 41 and theimage-side surface 42 of the fourth lens element 40 are asphericalsurfaces, but it is not limited thereto.

The fifth lens element 50 has positive refracting power. An optical axisregion 53 of the object-side surface 51 of the fifth lens element 50 isconcave, and a periphery region 54 of the object-side surface 51 of thefifth lens element 50 is concave. An optical axis region 56 of theimage-side surface 52 of the fifth lens element 50 is convex, and aperiphery region 57 of the image-side surface 52 of the fifth lenselement 50 is convex. Besides, both the object-side surface 51 and theimage-side surface 52 of the fifth lens element 50 are asphericalsurfaces, but it is not limited thereto.

The sixth lens element 60 has negative refracting power. An optical axisregion 63 of the object-side surface 61 of the sixth lens element 60 isconcave, and a periphery region 64 of the object-side surface 61 of thesixth lens element 60 is concave. An optical axis region 66 of theimage-side surface 62 of the sixth lens element 60 is convex, and aperiphery region 67 of the image-side surface 62 of the sixth lenselement 60 is convex. Besides, both the object-side surface 61 and theimage-side surface 62 of the sixth lens element 60 are asphericalsurfaces, but it is not limited thereto.

The seventh lens element 70 has positive refracting power. An opticalaxis region 73 of the object-side surface 71 of the seventh lens element70 is convex, and a periphery region 74 of the object-side surface 71 ofthe seventh lens element 70 is concave. An optical axis region 76 of theimage-side surface 72 of the seventh lens element 70 is concave, and aperiphery region 77 of the image-side surface 72 of the seventh lenselement 70 is convex. Besides, both the object-side surface 71 and theimage-side surface 72 of the seventh lens element 70 are asphericalsurfaces, but it is not limited thereto.

The eighth lens element 80 has negative refracting power. An opticalaxis region 83 of the object-side surface 81 of the eighth lens element80 is convex, and a periphery region 84 of the object-side surface 81 ofthe eighth lens element 80 is concave. An optical axis region 86 of theimage-side surface 82 of the eighth lens element 80 is concave, and aperiphery region 87 of the image-side surface 82 of the eighth lenselement 80 is convex. Besides, both the object-side surface 81 and theimage-side surface 82 of the eighth lens element 80 are asphericalsurfaces, but it is not limited thereto.

In the first lens element 10, the second lens element 20, the third lenselement 30, the fourth lens element 40, the fifth lens element 50, thesixth lens element 60, the seventh lens element 70 and the eighth lenselement 80 of the optical imaging lens element 1 of the presentinvention, there are 16 surfaces, such as the object-side surfaces11/21/31/41/51/61/71/81 and the image-side surfaces12/22/32/42/52/62/72/82. If a surface is aspherical, these asphericcoefficients are defined according to the following formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}{a_{2i} \times Y^{2i}}}}$

In which:R represents the curvature radius of the lens element surface;Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis and the tangent plane of the vertex on the opticalaxis of the aspherical surface);Y represents a vertical distance from a point on the aspherical surfaceto the optical axis;K is a conic constant; anda_(2i) is the aspheric coefficient of the 2i^(th) order.

The optical data of the first example of the optical imaging lens 1 areshown in FIG. 24 while the aspheric surface data are shown in FIG. 25.In the present examples of the optical imaging lens, the f-number of theentire optical imaging lens element system is Fno, EFL is the effectivefocal length, HFOV stands for the half field of view which is half ofthe field of view of the entire optical imaging lens element system, andthe unit for the curvature radius, the thickness and the focal length isin millimeters (mm). In this example, EFL=4.792 mm; HFOV=44.342 degrees;TTL=5.670 mm; Fno=1.690; ImgH=4.500 mm.

Second Example

Please refer to FIG. 8 which illustrates the second example of theoptical imaging lens 1 of the present invention. It is noted that fromthe second example to the following examples, in order to simplify thefigures, only the components different from what the first example has,and the basic lens elements will be labeled in figures. Other componentsthat are the same as what the first example has, such as the object-sidesurface, the image-side surface, the portion in a vicinity of theoptical axis and the portion in a vicinity of its periphery will beomitted in the following examples. Please refer to FIG. 9A for thelongitudinal spherical aberration on the image plane 91 of the secondexample, please refer to FIG. 9B for the field curvature aberration onthe sagittal direction, please refer to FIG. 9C for the field curvatureaberration on the tangential direction, and please refer to FIG. 9D forthe distortion aberration. The components in this example are similar tothose in the first example, but the optical data such as the curvatureradius, the lens thickness, the aspheric surface or the back focallength in this example are different from the optical data in the firstexample. Besides, in this example, the optical axis region 26 of theimage-side surface 22 of the second lens element 20 is concave, theoptical axis region 53 of the object-side surface 51 of the fifth lenselement 50 is convex, the optical axis region 56 of the image-sidesurface 52 of the fifth lens element 50 is concave, the optical axisregion 66 of the image-side surface 62 of the sixth lens element 60 isconcave, the eighth lens element 80 has positive refracting power.

The optical data of the second example of the optical imaging lens areshown in FIG. 26 while the aspheric surface data are shown in FIG. 27.In this example, EFL=3.439 mm; HFOV=44.560 degrees; TTL=5.026 mm;Fno=1.550; ImgH=4.500 mm. In particular: (1) The system length of theoptical imaging lens TTL in this example is shorter than the systemlength of the optical imaging lens TTL in the first example; (2) TheHFOV in this example is larger than the HFOV in the first example; (3)The f-number in this example is smaller than the f-number in the firstexample; (4) The longitudinal spherical aberration in this example issmaller than the longitudinal spherical aberration in the first example;(5) The field curvature aberration on the sagittal direction in thisexample is smaller than the field curvature aberration on the sagittaldirection in the first example.

Third Example

Please refer to FIG. 10 which illustrates the third example of theoptical imaging lens 1 of the present invention. Please refer to FIG.11A for the longitudinal spherical aberration on the image plane 91 ofthe third example; please refer to FIG. 11B for the field curvatureaberration on the sagittal direction; please refer to FIG. 11C for thefield curvature aberration on the tangential direction; and please referto FIG. 11D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 26 of the image-side surface 22 of the second lens element 20 isconcave, the optical axis region 53 of the object-side surface 51 of thefifth lens element 50 is convex, the optical axis region 56 of theimage-side surface 52 of the fifth lens element 50 is concave, theoptical axis region 66 of the image-side surface 62 of the sixth lenselement 60 is concave.

The optical data of the third example of the optical imaging lens areshown in FIG. 28 while the aspheric surface data are shown in FIG. 29.In this example, EFL=3.597 mm; HFOV=44.483 degrees; TTL=5.147 mm;Fno=1.550; ImgH=4.500 mm. In particular: (1) The system length of theoptical imaging lens TTL in this example is shorter than the systemlength of the optical imaging lens TTL in the first example; (2) TheHFOV in this example is larger than the HFOV in the first example; (3)The f-number in this example is smaller than the f-number in the firstexample; (4) The longitudinal spherical aberration in this example issmaller than the longitudinal spherical aberration in the first example;(5) The field curvature aberration on the sagittal direction in thisexample is smaller than the field curvature aberration on the sagittaldirection in the first example.

Fourth Example

Please refer to FIG. 12 which illustrates the fourth example of theoptical imaging lens 1 of the present invention. Please refer to FIG.13A for the longitudinal spherical aberration on the image plane 91 ofthe fourth example; please refer to FIG. 13B for the field curvatureaberration on the sagittal direction; please refer to FIG. 13C for thefield curvature aberration on the tangential direction; and please referto FIG. 13D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 26 of the image-side surface 22 of the second lens element 20 isconcave, the optical axis region 53 of the object-side surface 51 of thefifth lens element 50 is convex, the optical axis region 56 of theimage-side surface 52 of the fifth lens element 50 is concave, theoptical axis region 63 of the object-side surface 61 of the sixth lenselement 60 is convex, the optical axis region 66 of the image-sidesurface 62 of the sixth lens element 60 is concave.

The optical data of the fourth example of the optical imaging lens areshown in FIG. 30 while the aspheric surface data are shown in FIG. 31.In this example, EFL=3.564 mm; HFOV=44.603 degrees; TTL=5.033 mm;Fno=1.550; ImgH=4.500 mm. In particular: (1) The system length of theoptical imaging lens TTL in this example is shorter than the systemlength of the optical imaging lens TTL in the first example; (2) TheHFOV in this example is larger than the HFOV in the first example; 3.The f-number in this example is smaller than the f-number in the firstexample; (4) The longitudinal spherical aberration in this example issmaller than the longitudinal spherical aberration in the first example;(5) The field curvature aberration on the sagittal direction in thisexample is smaller than the field curvature aberration on the sagittaldirection in the first example.

Fifth Example

Please refer to FIG. 14 which illustrates the fifth example of theoptical imaging lens 1 of the present invention. Please refer to FIG.15A for the longitudinal spherical aberration on the image plane 91 ofthe fifth example; please refer to FIG. 15B for the field curvatureaberration on the sagittal direction; please refer to FIG. 15C for thefield curvature aberration on the tangential direction, and please referto FIG. 15D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 23 of the object-side surface 21 of the second lens element 20 isconvex, the optical axis region 26 of the image-side surface 22 of thesecond lens element 20 is concave, the optical axis region 46 of theimage-side surface 42 of the fourth lens element 40 is concave, theoptical axis region 53 of the object-side surface 51 of the fifth lenselement 50 is convex, the optical axis region 56 of the image-sidesurface 52 of the fifth lens element 50 is concave, the optical axisregion 66 of the image-side surface 62 of the sixth lens element 60 isconcave.

The optical data of the fifth example of the optical imaging lens areshown in FIG. 32 while the aspheric surface data are shown in FIG. 33.In this example, EFL=4.552 mm; HFOV=39.306 degrees; TTL=5.743 mm;Fno=1.700; ImgH=4.500 mm. In particular: (1) The longitudinal sphericalaberration in this example is smaller than the longitudinal sphericalaberration in the first example; (2) The field curvature aberration onthe sagittal direction in this example is smaller than the fieldcurvature aberration on the sagittal direction in the first example; (3)The field curvature aberration on the tangential direction in thisexample is smaller than the field curvature aberration on the tangentialdirection in the first example.

Sixth Example

Please refer to FIG. 16 which illustrates the sixth example of theoptical imaging lens 1 of the present invention. Please refer to FIG.17A for the longitudinal spherical aberration on the image plane 91 ofthe sixth example; please refer to FIG. 17B for the field curvatureaberration on the sagittal direction; please refer to FIG. 17C for thefield curvature aberration on the tangential direction, and please referto FIG. 17D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 23 of the object-side surface 21 of the second lens element 20 isconvex, the optical axis region 26 of the image-side surface 22 of thesecond lens element 20 is concave, the optical axis region 46 of theimage-side surface 42 of the fourth lens element 40 is concave, theoptical axis region 53 of the object-side surface 51 of the fifth lenselement 50 is convex, the optical axis region 56 of the image-sidesurface 52 of the fifth lens element 50 is concave, the optical axisregion 66 of the image-side surface 62 of the sixth lens element 60 isconcave.

The optical data of the sixth example of the optical imaging lens areshown in FIG. 34 while the aspheric surface data are shown in FIG. 35.In this example, EFL=4.327 mm; HFOV=39.143 degrees; TTL=5.744 mm;Fno=1.700; ImgH=4.500 mm. In particular: (1) The longitudinal sphericalaberration in this example is smaller than the longitudinal sphericalaberration in the first example; (2) The field curvature aberration onthe sagittal direction in this example is smaller than the fieldcurvature aberration on the sagittal direction in the first example; (3)The field curvature aberration on the tangential direction in thisexample is smaller than the field curvature aberration on the tangentialdirection in the first example.

Seventh Example

Please refer to FIG. 18 which illustrates the seventh example of theoptical imaging lens 1 of the present invention. Please refer to FIG.19A for the longitudinal spherical aberration on the image plane 91 ofthe seventh example; please refer to FIG. 19B for the field curvatureaberration on the sagittal direction; please refer to FIG. 19C for thefield curvature aberration on the tangential direction, and please referto FIG. 19D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 23 of the object-side surface 21 of the second lens element 20 isconvex, the optical axis region 26 of the image-side surface 22 of thesecond lens element 20 is concave, the optical axis region 46 of theimage-side surface 42 of the fourth lens element 40 is concave, theoptical axis region 53 of the object-side surface 51 of the fifth lenselement 50 is convex, the optical axis region 56 of the image-sidesurface 52 of the fifth lens element 50 is concave, the optical axisregion 66 of the image-side surface 62 of the sixth lens element 60 isconcave.

The optical data of the seventh example of the optical imaging lens areshown in FIG. 36 while the aspheric surface data are shown in FIG. 37.In this example, EFL=4.381 mm; HFOV=40.147 degrees; TTL=5.750 mm;Fno=1.700; ImgH=4.500 mm. In particular: (1) The longitudinal sphericalaberration in this example is smaller than the longitudinal sphericalaberration in the first example; (2) The field curvature aberration onthe sagittal direction in this example is smaller than the fieldcurvature aberration on the sagittal direction in the first example; (3)The field curvature aberration on the tangential direction in thisexample is smaller than the field curvature aberration on the tangentialdirection in the first example.

Eighth Example

Please refer to FIG. 20 which illustrates the eighth example of theoptical imaging lens 1 of the present invention. Please refer to FIG.21A for the longitudinal spherical aberration on the image plane 91 ofthe eighth example; please refer to FIG. 21B for the field curvatureaberration on the sagittal direction; please refer to FIG. 21C for thefield curvature aberration on the tangential direction, and please referto FIG. 21D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 23 of the object-side surface 21 of the second lens element 20 isconvex, the optical axis region 26 of the image-side surface 22 of thesecond lens element 20 is concave, the fourth lens element 40 haspositive refracting power, the fifth lens element 50 has negativerefracting power, the optical axis region 56 of the image-side surface52 of the fifth lens element 50 is concave, the optical axis region 66of the image-side surface 62 of the sixth lens element 60 is concave.

The optical data of the eighth example of the optical imaging lens areshown in FIG. 38 while the aspheric surface data are shown in FIG. 39.In this example, EFL=4.360 mm; HFOV=39.885 degrees; TTL=5.694 mm;Fno=1.700; ImgH=4.500 mm. In particular: (1) The longitudinal sphericalaberration in this example is smaller than the longitudinal sphericalaberration in the first example; (2) The field curvature aberration onthe sagittal direction in this example is smaller than the fieldcurvature aberration on the sagittal direction in the first example; (3)The field curvature aberration on the tangential direction in thisexample is smaller than the field curvature aberration on the tangentialdirection in the first example.

Ninth Example

Please refer to FIG. 22 which illustrates the ninth example of theoptical imaging lens 1 of the present invention. Please refer to FIG.23A for the longitudinal spherical aberration on the image plane 91 ofthe ninth example; please refer to FIG. 23B for the field curvatureaberration on the sagittal direction; please refer to FIG. 23C for thefield curvature aberration on the tangential direction, and please referto FIG. 23D for the distortion aberration. The components in thisexample are similar to those in the first example, but the optical datasuch as the curvature radius, the lens thickness, the aspheric surfaceor the back focal length in this example are different from the opticaldata in the first example. Besides, in this example, the optical axisregion 23 of the object-side surface 21 of the second lens element 20 isconvex, the optical axis region 26 of the image-side surface 22 of thesecond lens element 20 is concave, the fifth lens element 50 hasnegative refracting power, the optical axis region 53 of the object-sidesurface 51 of the fifth lens element 50 is convex, the optical axisregion 56 of the image-side surface 52 of the fifth lens element 50 isconcave, the sixth lens element 60 has positive refracting power, theoptical axis region 63 of the object-side surface 61 of the sixth lenselement 60 is convex, the optical axis region 66 of the image-sidesurface 62 of the sixth lens element 60 is concave.

The optical data of the ninth example of the optical imaging lens areshown in FIG. 40 while the aspheric surface data are shown in FIG. 41.In this example, EFL=4.080 mm; HFOV=41.957 degrees; TTL=5.430 mm;Fno=1.700; ImgH=4.500 mm. In particular: (1) The system length of theoptical imaging lens TTL in this example is shorter than the systemlength of the optical imaging lens TTL in the first example; (2) Thelongitudinal spherical aberration in this example is smaller than thelongitudinal spherical aberration in the first example; (3) The fieldcurvature aberration on the sagittal direction in this example issmaller than the field curvature aberration on the sagittal direction inthe first example; (4) The field curvature aberration on the tangentialdirection in this example is smaller than the field curvature aberrationon the tangential direction in the first example.

Some important ratios in each example are shown in FIG. 42.

Each embodiment of the present invention provides an optical imaginglens which has good imaging quality. For example, the following lenscurvature configuration may effectively reduce the field curvatureaberration and the distortion aberration to optimize the imaging qualityof the optical imaging lens. Furthermore, the present invention has thecorresponding advantages:

1. The optical imaging lens of the present invention satisfies that thefirst lens element has positive refracting power and the optical axisregion of the object-side surface of the eighth lens element is convex.If the following conditions are satisfied at the same time, it isadvantageous to increase the aperture and the image height whilereducing the total system length:(1) The optical axis region of the image-side surface of the first lenselement is concave, the second lens element has negative refractingpower, the periphery region of the object-side surface of the secondlens element is concave, and D61t82/D21t42≥1.750, and the preferablerange is 1.750≤D61t82/D21t42≤3.000.(2) The periphery region of the image-side surface of the first lenselement is concave, the periphery region of the image-side surface ofthe fourth lens element is convex, the periphery region of theobject-side surface of the sixth lens element is concave, the seventhlens element has positive refracting power, and D61t82/D21t42≥2.000, andthe preferable range is 2.000≤D61t82/D21t42≤3 0.000.(3) The optical axis region of the image-side surface of the first lenselement is concave, the periphery region of the object-side surface ofthe second lens element is concave, the periphery region of theimage-side surface of the third lens element is convex, andν1+ν2+ν3+ν4+ν5≤205.000, the preferable range is130.000≤ν1+ν2+ν3+ν4+ν5≤205.000.2. The optical imaging lens of the present invention further satisfiesthe conditions of ν4+ν5≤70.100, ν4≤35.000 and ν7≥49.000, which isfavorable for correcting the chromatic aberration of the optical imaginglens. And the preferable ranges are 30.000≤ν4+ν5≤70.100;15.000≤ν4≤35.000; 49.000≤ν7≤60.000, when the condition of30.000≤ν4+ν5≤60.000 is satisfied, the longitudinal spherical aberrationcan be further improved.3. The optical imaging lens of the present invention further satisfiesthe following conditions, which is helpful to maintain the focal lengthand the optical parameters of the optical imaging lens in a propervalue, to prevent any parameter from being too large to be unfavorableto the aberration correction of the overall optical imaging lens, or toprevent any parameter from being too small to affect assembly or toimprove manufacturing difficulty:EFL*Fno/ImgH≤1.800, and the preferable range is1.000≤EFL*Fno/ImgH≤1.800.4. The optical imaging lens of the present invention further satisfiesthe following conditions, which is helpful to maintain the thickness andspacing of each lens element at appropriate values, to prevent anyparameter from being too large to be unfavorable to the overall thinningof the optical imaging lens, or to prevent any parameter from being toosmall to affect assembly or to improve manufacturing difficulty:(1) TTL/ImgH≤1.300, and the preferable range is 1.000≤TTL/ImgH≤1.300;(2) TL*Fno/ImgH≤2.000, and the preferable range is1.500≤TL*Fno/ImgH≤2.000;(3) ALT/AAG≤2.000, and the preferable range is 1.000≤ALT/AAG≤2.000;(4) (ALT+BFL)/AAG48≤4.150, and the preferable range is1.500≤(ALT+BFL)/AAG48≤4.150;(5) ALT/(T3+T6+G12)≤3.900, and the preferable range is2.000≤ALT/(T3+T6+G12)≤3.900;(6) (T1+T2+T5+G23)/(T3+G45)≤1.900, and the preferable range is0.700≤(T1+T2+T5+G23)/(T3+G45)≤1.900;(7) (T1+T2+T5+G34)/(T3+G56)≤2.000, and the preferable range is0.600≤(T1+T2+T5+G34)/(T3+G56)≤2.000;(8) (T1+T2+T5+G67)/(T3+G78)≤2.000, and the preferable range is0.500≤(T1+T2+T5+G67)/(T3+G78)≤2.000;(9) (T7+T8+G23)/(T4+G12+G45)≤3.200, and the preferable range is0.600≤(T7+T8+G23)/(T4+G12+G45)≤3.200;(10) (T7+T8+G34)/(T4+G12+G56)≤2.200, and the preferable range is0.900≤(T7+T8+G34)/(T4+G12+G56)≤2.200;(11) (T7+T8+G67)/(T4+G12+G78)≤2.400, and the preferable range is0.500≤(T7+T8+G67)/(T4+G12+G78)≤2.400;(12) D42t71/(T3+G12)≤2.700, and the preferable range is1.200≤D42t71/(T3+G12)≤2.700; and(13) D42t71/(T3+G78)≤2.200, and the preferable range is0.600≤D42t71/(T3+G78)≤2.200.

By observing three representative wavelengths of 470 nm, 555 nm and 650nm in each embodiment of the present invention, it is suggested off-axislight of different heights of every wavelength all concentrates on theimage plane, and deviations of every curve also reveal that off-axislight of different heights are well controlled so the examples doimprove the spherical aberration, the astigmatic aberration and thedistortion aberration. In addition, by observing the imaging qualitydata the distances amongst the three representing different wavelengthsof 470 nm, 555 nm and 650 nm are pretty close to one another, whichmeans the embodiments of the present invention are able to concentratelight of the three representing different wavelengths so that theaberration is greatly improved. Given the above, it is understood thatthe embodiments of the present invention provides outstanding imagingquality.

In addition, any arbitrary combination of the parameters of theembodiments can be selected to increase the lens limitation so as tofacilitate the design of the same structure of the present invention.

In the light of the unpredictability of the optical imaging lens, thepresent invention suggests the above principles to have a shorter totallength of the optical imaging lens, a larger aperture available, betterimaging quality or a better fabrication yield to overcome the drawbacksof prior art.

In addition to the above ratios, one or more conditional formulae may beoptionally combined to be used in the embodiments of the presentinvention and the present invention is not limit to this. The curvaturesof each lens element or multiple lens elements may be fine-tuned toresult in more fine structures to enhance the performance or theresolution. The above limitations may be selectively combined in theembodiments without causing inconsistency.

The numeral value ranges within the maximum and minimum values obtainedfrom the combination ratio relationships of the optical parametersdisclosed in each embodiment of the invention can all be implementedaccordingly.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens comprising a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially from an object side to an image side along an optical axis, each of the first lens element to the eighth lens element having an object-side surface facing toward the object side to allow imaging rays to pass through as well as an image-side surface facing toward the image side to allow the imaging rays to pass through, wherein: the first lens element has positive refracting power, and an optical axis region of the image-side surface of the first lens element is concave; the second lens has negative refracting power, and a periphery region of the object-side surface of the second lens element is concave; an optical axis region of the object-side surface of the eighth lens element is convex; the lens elements having refracting power included by the optical imaging lens are only the eight lens elements described above, wherein the optical imaging lens satisfies the relationships: D61t82/D21t42≥1.750, wherein D61t82 is a distance from the object-side surface of the sixth lens element to the image-side surface of the eighth lens element along the optical axis, D21t42 is a distance from the object-side surface of the second lens element to the image-side surface of the fourth lens element along the optical axis.
 2. The optical imaging lens of claim 1, wherein ν4 is an Abbe number of the fourth lens element, ν5 is an Abbe number of the fifth lens element, and the optical imaging lens satisfies the relationship: ν4+ν5≤70.100.
 3. The optical imaging lens of claim 1, wherein EFL is an effective focal length of the optical imaging lens, Fno is a f-number of the optical imaging lens, ImgH is an image height of the optical imaging lens, and the optical imaging lens satisfies the relationship: EFL*Fno/ImgH≤1.800.
 4. The optical imaging lens of claim 1, wherein ALT is a sum of the thicknesses of eight lens elements from the first lens element to the eighth lens element along the optical axis, AAG is a sum of seven air gaps from the first lens element to the eighth lens element along the optical axis, and the optical imaging lens satisfies the relationship: ALT/AAG≤2.000.
 5. The optical imaging lens of claim 1, wherein T1 is a thickness of the first lens element along the optical axis, T2 is a thickness of the second lens element along the optical axis, T3 is a thickness of the third lens element along the optical axis, T5 is a thickness of the fifth lens element along the optical axis, G23 is an air gap between the second lens element and the third lens element along the optical axis, G45 is an air gap between the fourth lens element and the fifth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (T1+T2+T5+G23)/(T3+G45)≤1.900.
 6. The optical imaging lens of claim 1, wherein T4 is a thickness of the fourth lens element along the optical axis, T7 is a thickness of the seventh lens element along the optical axis, T8 is a thickness of the eighth lens element along the optical axis, G12 is an air gap between the first lens element and the second lens element along the optical axis, G23 is an air gap between the second lens element and the third lens element along the optical axis, G45 is an air gap between the fourth lens element and the fifth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (T7+T8+G23)/(T4+G12+G45)≤3.200.
 7. The optical imaging lens of claim 1, wherein T3 is a thickness of the third lens element along the optical axis, G12 is an air gap between the first lens element and the second lens element along the optical axis, D42t71 is a distance from the image-side surface of the fourth lens element to the object-side surface of the seventh lens element along the optical axis, and the optical imaging lens satisfies the relationship: D42t71/(T3+G12)≤2.700.
 8. An optical imaging lens comprising a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially from an object side to an image side along an optical axis, each of the first lens element to the eighth lens element having an object-side surface facing toward the object side to allow imaging rays to pass through as well as an image-side surface facing toward the image side to allow the imaging rays to pass through, wherein: the first lens element has positive refracting power, and a periphery region of the image-side surface of the first lens element is concave; the periphery region of the image-side surface of the fourth lens element is convex; a periphery region of the object-side surface of the sixth lens element is concave; the seventh lens element has positive refracting power; an optical axis region of the object-side surface of the eighth lens element is convex; the lens elements having refracting power included by the optical imaging lens are only the eight lens elements described above, wherein the optical imaging lens satisfies the relationships: D61t82/D21t42≥2.000, wherein D61t82 is a distance from the object-side surface of the sixth lens element to the image-side surface of the eighth lens element along the optical axis, D21t42 is a distance from the object-side surface of the second lens element to the image-side surface of the fourth lens element along the optical axis.
 9. The optical imaging lens of claim 8, wherein ν4 is an Abbe number of the fourth lens element, and the optical imaging lens satisfies the relationship: ν4≤35.000.
 10. The optical imaging lens of claim 8, wherein TTL is the distance from the object-side surface of the first lens element to an imaging plane along the optical axis, ImgH is an image height of the optical imaging lens, and the optical imaging lens satisfies the relationship: TTL/ImgH≤1.300.
 11. The optical imaging lens of claim 8, wherein ALT is a sum of the thicknesses of eight lens elements from the first lens element to the eighth lens element along the optical axis, BFL is a distance from the image-side surface of the eighth lens element to an image plane along the optical axis, AAG48 is a sum of four air gaps from the fourth lens element to the eighth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (ALT+BFL)/AAG48≤4.150.
 12. The optical imaging lens of claim 8, wherein T1 is a thickness of the first lens element along the optical axis, T2 is a thickness of the second lens element along the optical axis, T3 is a thickness of the third lens element along the optical axis, T5 is a thickness of the fifth lens element along the optical axis, G34 is an air gap between the third lens element and the fourth lens element along the optical axis, G56 is an air gap between the fifth lens element and the sixth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (T1+T2+T5+G34)/(T3+G56)≤2.000.
 13. The optical imaging lens of claim 8, wherein T4 is a thickness of the fourth lens element along the optical axis, T7 is a thickness of the seventh lens element along the optical axis, T8 is a thickness of the eighth lens element along the optical axis, G12 is an air gap between the first lens element and the second lens element along the optical axis, G34 is an air gap between the third lens element and the fourth lens element along the optical axis, G56 is an air gap between the fifth lens element and the sixth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (T7+T8+G34)/(T4+G12+G56)≤2.200.
 14. The optical imaging lens of claim 8, wherein T3 is a thickness of the third lens element along the optical axis, G78 is an air gap between the seventh lens element and the eighth lens element along the optical axis, D42t71 is a distance from the image-side surface of the fourth lens element to the object-side surface of the seventh lens element along the optical axis, and the optical imaging lens satisfies the relationship: D42t71/(T3+G78)≤2.200.
 15. An optical imaging lens comprising: a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element sequentially from an object side to an image side along an optical axis, each of the first lens element to the eighth lens element having an object-side surface facing toward the object side to allow imaging rays to pass through as well as an image-side surface facing toward the image side to allow the imaging rays to pass through, wherein: the first lens element has positive refracting power, and an optical axis region of the image-side surface of the first lens element is concave; a periphery region of the object-side surface of the second lens element is concave; a periphery region of the image-side surface of the third lens element is convex; an optical axis region of the object-side surface of the eighth lens element is convex; the lens elements having refracting power included by the optical imaging lens are only the eight lens elements described above, wherein the optical imaging lens satisfies the relationships: ν1+ν2+ν3+ν4+ν5≤205.000, ν1 is an Abbe number of the first lens element, ν2 is an Abbe number of the second lens element, ν3 is an Abbe number of the third lens element, ν4 is an Abbe number of the fourth lens element; ν5 is an Abbe number of the fifth lens element.
 16. The optical imaging lens of claim 15, wherein ν7 is an Abbe number of the seventh lens element, and the optical imaging lens satisfies the relationship: 49.000≤ν7≤60.000.
 17. The optical imaging lens of claim 15, wherein TL is a distance from the object-side surface of the first lens element to the image-side surface of the eighth lens element along the optical axis, Fno is a f-number of the optical imaging lens, ImgH is an image height of the optical imaging lens, and the optical imaging lens satisfies the relationship: TL*Fno/ImgH≤2.000.
 18. The optical imaging lens of claim 15, wherein T3 is a thickness of the third lens element along the optical axis, T6 is a thickness of the sixth lens element along the optical axis, G12 is an air gap between the first lens element and the second lens element along the optical axis, ALT is a sum of the thicknesses of eight lens elements from the first lens element to the eighth lens element along the optical axis, and the optical imaging lens satisfies the relationship: ALT/(T3+T6+G12)≤3.100.
 19. The optical imaging lens of claim 15, wherein T1 is a thickness of the first lens element along the optical axis, T2 is a thickness of the second lens element along the optical axis, T3 is a thickness of the third lens element along the optical axis, T5 is a thickness of the fifth lens element along the optical axis, G67 is an air gap between the sixth lens element and the seventh lens element along the optical axis, G78 is an air gap between the seventh lens element and the eighth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (T1+T2+T5+G67)/(T3+G78)≤2.000.
 20. The optical imaging lens of claim 15, wherein T4 is a thickness of the fourth lens element along the optical axis, T7 is a thickness of the seventh lens element along the optical axis, T8 is a thickness of the eighth lens element along the optical axis, G12 is an air gap between the first lens element and the second lens element along the optical axis, G67 is an air gap between the sixth lens element and the seventh lens element along the optical axis, G78 is an air gap between the seventh lens element and the eighth lens element along the optical axis, and the optical imaging lens satisfies the relationship: (T7+T8+G67)/(T4+G12+G78)≤2.400. 